1. Field of the Invention
The present invention relates to compositions comprising an effective amount of sulphur; an effective amount of zinc sulphate or zinc oxide and at least one agrochemically acceptable excipient. The invention further relates to a method of application of the compositions to crops.
2. Description of the Related Art
The role of sulphur as an essential and a growing nutrient and fertilizer has been long known. Sulphur deficiency has become widespread over the past several decades in most of the agricultural areas of the world, resulting in sulphur being indicated as a limiting factor to high yields and fertilizer efficiency.
The role of zinc as a micronutrient has also been known. The role of zinc and its association with Khaira disease in particular, in paddy (rice) cultivated soils at large is well known. When a plant has an inadequate supply of zinc, the biochemical functions become impaired and thus the health and growth of the plants are adversely affected resulting in lower yield or even crop failure and poorer crop quality.
According to W.H.O close to fifty percent of world cereal soils are deficient in zinc and it is estimated that one third of world's population is at risk of zinc deficiency which can lead to health problems including poor immune response and impaired growth and development. Globally, zinc deficiency ranks eleventh among twenty risk factors. W.H.O attributes 8,00,000 deaths world wide each year due to zinc deficiency. Therefore, improving zinc nutrients status of food crops becomes a priority for fighting malnutrition in humans and animals.
When commercially available zinc and sulphur fertilisers are applied to the crops, these fertilisers are required in large doses, as the nutrients are not available immediately for plant uptake. Also, since these nutrients are not readily available for plant uptake due to their formulations, these fertilisers are also leached, washed away and wasted. No suitable fertilizer composition comprising both sulphur and zinc are known or available which can be effectively used in micro irrigation systems to meet the requirements of the plants.
Furthermore, granular sulphur and zinc fertilizers such as sulphur and zinc oxide, for instance, which are formulated with certain excipients, for example, bentonite, are not water dispersible. These conventional sulphur and zinc fertilizers swell and block micro irrigation systems or nozzles during the application. Hence, they cannot be effectively used in drip irrigation, which is also becoming more essential as labour shortage increases and water becomes a scarce resource. Furthermore, such fertilizers are in the form of prills or pellets or pastilles, and are also applied at much higher dosages to achieve desired levels of nutrition. This presents a great challenge to the user and to the environment.
Hence, there is a need to develop a composition, which provides sulphur and zinc to the soil in a timely manner as per the physiological needs of the plant, is water dispersible and can be efficiently used in micro irrigation systems, is user friendly, enhances yields, optimizes the uses of zinc and sulphur while reducing the cost of application and is yet used in lower quantities, thus minimizing any residues and overcomes the drawbacks presented by the prior art.